vendor/github.com/hashicorp/terraform/configs/parser.go

   1 package configs
   2
   3 import (
   4         "fmt"
   5         "strings"
   6
   7         "github.com/hashicorp/hcl2/hcl"
   8         "github.com/hashicorp/hcl2/hclparse"
   9         "github.com/spf13/afero"
  10 )
  11
  12 // Parser is the main interface to read configuration files and other related
  13 // files from disk.
  14 //
  15 // It retains a cache of all files that are loaded so that they can be used
  16 // to create source code snippets in diagnostics, etc.
  17 type Parser struct {
  18         fs afero.Afero
  19         p  *hclparse.Parser
  20 }
  21
  22 // NewParser creates and returns a new Parser that reads files from the given
  23 // filesystem. If a nil filesystem is passed then the system's "real" filesystem
  24 // will be used, via afero.OsFs.
  25 func NewParser(fs afero.Fs) *Parser {
  26         if fs == nil {
  27                 fs = afero.OsFs{}
  28         }
  29
  30         return &Parser{
  31                 fs: afero.Afero{Fs: fs},
  32                 p:  hclparse.NewParser(),
  33         }
  34 }
  35
  36 // LoadHCLFile is a low-level method that reads the file at the given path,
  37 // parses it, and returns the hcl.Body representing its root. In many cases
  38 // it is better to use one of the other Load*File methods on this type,
  39 // which additionally decode the root body in some way and return a higher-level
  40 // construct.
  41 //
  42 // If the file cannot be read at all -- e.g. because it does not exist -- then
  43 // this method will return a nil body and error diagnostics. In this case
  44 // callers may wish to ignore the provided error diagnostics and produce
  45 // a more context-sensitive error instead.
  46 //
  47 // The file will be parsed using the HCL native syntax unless the filename
  48 // ends with ".json", in which case the HCL JSON syntax will be used.
  49 func (p *Parser) LoadHCLFile(path string) (hcl.Body, hcl.Diagnostics) {
  50         src, err := p.fs.ReadFile(path)
  51
  52         if err != nil {
  53                 return nil, hcl.Diagnostics{
  54                         {
  55                                 Severity: hcl.DiagError,
  56                                 Summary:  "Failed to read file",
  57                                 Detail:   fmt.Sprintf("The file %q could not be read.", path),
  58                         },
  59                 }
  60         }
  61
  62         var file *hcl.File
  63         var diags hcl.Diagnostics
  64         switch {
  65         case strings.HasSuffix(path, ".json"):
  66                 file, diags = p.p.ParseJSON(src, path)
  67         default:
  68                 file, diags = p.p.ParseHCL(src, path)
  69         }
  70
  71         // If the returned file or body is nil, then we'll return a non-nil empty
  72         // body so we'll meet our contract that nil means an error reading the file.
  73         if file == nil || file.Body == nil {
  74                 return hcl.EmptyBody(), diags
  75         }
  76
  77         return file.Body, diags
  78 }
  79
  80 // Sources returns a map of the cached source buffers for all files that
  81 // have been loaded through this parser, with source filenames (as requested
  82 // when each file was opened) as the keys.
  83 func (p *Parser) Sources() map[string][]byte {
  84         return p.p.Sources()
  85 }
  86
  87 // ForceFileSource artificially adds source code to the cache of file sources,
  88 // as if it had been loaded from the given filename.
  89 //
  90 // This should be used only in special situations where configuration is loaded
  91 // some other way. Most callers should load configuration via methods of
  92 // Parser, which will update the sources cache automatically.
  93 func (p *Parser) ForceFileSource(filename string, src []byte) {
  94         // We'll make a synthetic hcl.File here just so we can reuse the
  95         // existing cache.
  96         p.p.AddFile(filename, &hcl.File{
  97                 Body:  hcl.EmptyBody(),
  98                 Bytes: src,
  99         })
 100 }